Lung cancer (LC) is one of the leading causes of death worldwide. Programmed cell death receptor 1 (PD-1) interacts with its ligand (PDL-1) on T cells inhibiting its functioning which may affect the patient's immunological response.

Investigate if there is a link between smoking and tissue expression of PDL-1 and vitamin D receptor (VDR) in lung cancer patients. In addition, the relation of vitamin D with smoking and these biochemical markers.

PDL-1 and VDR expressions were evaluated by real-time PCR in 54 lung cancer biopsy samples and 36 controls to prove this hypothesis. Vitamin D levels in the blood were measured using an ELISA.

Expressions of PDL-1 were significantly upregulated in LC patients than in controls. The highest expression was in stage II and in squamous cell carcinoma followed by small cell carcinoma then adenocarcinoma. However, VDR expressions and …